It is known to operate a mass transit vehicle in conjunction with an automatic vehicle control system and to operate the passenger doors of such a vehicle with suitable door command signals. It is necessary to sense when the vehicle is stopped at a station platform before the door open signal causes the passenger doors to open for the exit and entry of passengers. In addition as described in a published article entitled Automatic Train Control Concepts are implemented by modern equipement at pages 145 through 151 of the Westinghouse Engineer for September 1972 the vehicle door controls can be interlocked with vehicle zero speed detection to prevent automatic door opening before the vehicle has come to a stop.
A requirement of transit expressway and rapid transit vehicle door operation is that each door should be mechanically locked in a closed position before the vehicle is allowed to move along the track. It is known for this purpose to provide motion control apparatus for controlling double doors simultaneously as shown in U.S. Pat. No. 4,142,326 assigned to the same assignee as the present invention.